Kazumi Tokiwa is one of the two main protagonists of Futari wa Milky Holmes, where she forms the vigilante detective duo Feathers alongside her partner, Alice Myojingawa. Kazumi is a student at the Holmes Detective Academy, initially depicted as twelve years old. Hailing from a family of retired detectives, she is the only child of parents who once worked in the profession but have since stepped away from active duty. This family background heavily influences her path, as she holds a deep-seated aspiration to become a successful detective, a goal she actively pursues from a young age.

In terms of appearance, Kazumi is characterized by her short, light violet hair and brown eyes. She is consistently shown wearing a distinctive four-leaf clover hairpin, which serves as a symbol of her long-standing friendship with Alice. Her personality is defined by a strong sense of righteousness and a forward-moving, action-oriented nature. She is known to be straightforward and proactive, sometimes rushing into situations without extensive forethought. While this drive is a strength, she can be less adept at handling fine details, a trait that occasionally puts her at a disadvantage. This eagerness and tendency to act first can also make her susceptible to being tricked by others.

Kazumi possesses a supernatural ability known as a Toy, which manifests as the power to create a bow and arrows forged from light. This ability, named Arrow, is noted for its high accuracy and piercing power. She is the one who coins the name Feathers for their detective group. The true potential of her Toy is realized when it is combined with her partner Alice's barrier-based Toy, resulting in a significantly more powerful synergistic attack. This combination is a central element of their combat effectiveness as a team.

The core of Kazumi’s role and development is her profound relationship with Alice, her childhood friend and partner in Feathers. Their bond is depicted through various shared activities, such as going out for ice cream or watching sunsets on the beach while holding hands. However, their partnership is also a source of internal conflict for Kazumi. At one point, she is confronted by a senior detective who implies she might be more suited to be a phantom thief than a detective. This comment, combined with her own perception that Alice’s Toy has greater utility, fosters feelings of inferiority. This internal struggle reaches a critical point where Kazumi is invited to briefly join a phantom thief organization. She accepts this invitation to run away from her feelings of inadequacy, hoping to find a way to become stronger without harboring jealousy towards her closest friend. Ultimately, she reaffirms her own identity and commitment to being a detective, returning to Alice’s side to continue their work as Feathers.

Her motivations are driven by a proactive dedication to justice, inspired by the heroism of the original Milky Holmes detective agency. Her lineage as a child from a detective family initially seems to set her on this path, but her journey reveals a more personal battle with her own perceived limitations and the desire to stand as an equal beside her partner. Her key relationships beyond Alice include being mentored by the members of Milky Holmes, who also misunderstand her temporary departure as a quest for greater strength, and her family, who are aware of her secret activities.